Perry's Index to the Aesopica

Fables exist in many versions; here is one version in English:

ZEUS AND THE ANT

Long ago, the creature who is today an ant used to be a man who was always busy
farming. Still, he was not satisfied with the results of his own labour, so
he would steal from his neighbours' crops. Zeus became angry at his greedy behaviour
and turned him into the animal that now has the name of 'ant.' Yet even though
the man changed his shape, he did not change his habits, and even now he goes
around the fields gathering the fruits of other people's labour, storing them
up for himself. The fable shows that when someone with a wicked nature changes his appearance,
his behaviour remains the same.

Source:
Aesop's Fables. A new translation by Laura
Gibbs.
Oxford University Press (World's Classics): Oxford, 2002.
NOTE: New
cover, with new ISBN, published in 2008; contents of book unchanged.

You can find a compilation of Perry's index to the Aesopica in the gigantic appendix to his
edition of Babrius and Phaedrus for the Loeb Classical Library
(Harvard University Press: Cambridge, 1965). This book is an absolute must for anyone interested
in the Aesopic fable tradition. Invaluable.